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Xue L, Geurts F, Meijer E, de Borst MH, Gansevoort RT, Zietse R, Hoorn EJ, Salih M. Kidney phosphate wasting predicts poor outcome in polycystic kidney disease. Nephrol Dial Transplant 2024; 39:1105-1114. [PMID: 37985930 PMCID: PMC11249971 DOI: 10.1093/ndt/gfad247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Indexed: 11/22/2023] Open
Abstract
BACKGROUND Patients with autosomal dominant polycystic kidney disease (ADPKD) have disproportionately high levels of fibroblast growth factor 23 (FGF-23) for their chronic kidney disease stage, however only a subgroup develops kidney phosphate wasting. We assessed factors associated with phosphate wasting and hypothesize that it identifies patients with more severe disease and predicts disease progression. METHODS We included 604 patients with ADPKD from a multicenter prospective observational cohort (DIPAK; Developing Intervention Strategies to Halt Progression of Autosomal Dominant Polycystic Kidney Disease) in four university medical centers in the Netherlands. We measured parathyroid hormone (PTH) and total plasma FGF-23 levels, and calculated the ratio of tubular maximum reabsorption rate of phosphate to glomerular filtration rate (TmP/GFR) with <0.8 mmol/L defined as kidney phosphate wasting. We analysed the association of TmP/GFR with estimated GFR (eGFR) decline over time and the risk for a composite kidney outcome (≥30% eGFR decline, kidney failure or kidney replacement therapy). RESULTS In our cohort (age 48 ± 12 years, 39% male, eGFR 63 ± 28 mL/min/1.73 m2), 59% of patients had phosphate wasting. Male sex [coefficient -0.2, 95% confidence interval (CI) -0.2; -0.1], eGFR (0.002, 95% CI 0.001; 0.004), FGF-23 (0.1, 95% CI 0.03; 0.2), PTH (-0.2, 95% CI -0.3; -0.06) and copeptin (-0.08, 95% CI -0.1; -0.08) were associated with TmP/GFR. Corrected for PTH, FGF-23 and eGFR, every 0.1 mmol/L decrease in TmP/GFR was associated with a greater eGFR decline of 0.2 mL/min/1.73 m2/year (95% CI 0.01; 0.3) and an increased hazard ratio of 1.09 (95% CI 1.01; 1.18) of the composite kidney outcome. CONCLUSION Our study shows that in patients with ADPKD, phosphate wasting is prevalent and associated with more rapid disease progression. Phosphate wasting may be a consequence of early proximal tubular dysfunction and insufficient suppression of PTH.
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Affiliation(s)
- Laixi Xue
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Frank Geurts
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Esther Meijer
- Department of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Martin H de Borst
- Department of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Ron T Gansevoort
- Department of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert Zietse
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ewout J Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Mahdi Salih
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
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Torres JA, Holznecht N, Asplund DA, Amarlkhagva T, Kroes BC, Rebello J, Agrawal S, Weimbs T. A combination of β-hydroxybutyrate and citrate ameliorates disease progression in a rat model of polycystic kidney disease. Am J Physiol Renal Physiol 2024; 326:F352-F368. [PMID: 38095025 PMCID: PMC11207547 DOI: 10.1152/ajprenal.00205.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/11/2023] [Accepted: 12/11/2023] [Indexed: 02/15/2024] Open
Abstract
Our research has shown that interventions producing a state of ketosis are highly effective in rat, mouse, and cat models of polycystic kidney disease (PKD), preventing and partially reversing cyst growth and disease progression. The ketone β-hydroxybutyrate (BHB) appears to underlie this effect. In addition, we have demonstrated that naturally formed microcrystals within kidney tubules trigger a renoprotective response that facilitates tubular obstruction clearance in healthy animals but, alternatively, leads to cyst formation in PKD. The administration of citrate prevents microcrystal formation and slows PKD progression. Juvenile Cy/+ rats, a nonorthologous PKD model, were supplemented from 3 to 8 wk of age with water containing titrated BHB, citrate, or in combination to find minimal effective and optimal dosages, respectively. Adult rats were given a reduced BHB/citrate combination or equimolar control K/NaCl salts from 8 to 12 wk of age. In addition, adult rats were placed in metabolic cages following BHB, citrate, and BHB/citrate administration to determine the impact on mineral, creatinine, and citrate excretion. BHB or citrate alone effectively ameliorates disease progression in juvenile rats, decreasing markers of cystic disease and, in combination, producing a synergistic effect. BHB/citrate leads to partial disease regression in adult rats with established cystic disease, inhibiting cyst formation and kidney injury. BHB/citrate confers benefits via multiple mechanisms, increases creatinine and citrate excretion, and normalizes mineral excretion. BHB and citrate are widely available and generally recognized as safe compounds and, in combination, exhibit high promise for supporting kidney health in polycystic kidney disease.NEW & NOTEWORTHY Combining β-hydroxybutyrate (BHB) and citrate effectively slows and prevents cyst formation and expansion in young Cy/+ rats using less BHB and citrate than when used alone, demonstrating synergy. In adult rats, the combination causes a partial reversal of existing disease, reducing cyst number and cystic area, preserving glomerular health, and decreasing markers of kidney injury. Our results suggest a safe and feasible strategy for supporting kidney health in polycystic kidney disease (PKD) using a combination of BHB and citrate.
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Affiliation(s)
- Jacob A Torres
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - Nickolas Holznecht
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - David A Asplund
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - Tselmeg Amarlkhagva
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - Bradley C Kroes
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - Juliette Rebello
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - Shagun Agrawal
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology, University of California-Santa Barbara, Santa Barbara, California, United States
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Lai S, Perrotta AM, Rotondi S, Zippo F, Menè P, Tartaglione L, Pellicano C, Gigante A, Tinti F, Mazzei M, Mazzaferro S. Tubular changes in autosomal dominant polycystic kidney disease patients: observational study. J Nephrol 2024; 37:531-533. [PMID: 37955820 DOI: 10.1007/s40620-023-01794-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/26/2023] [Indexed: 11/14/2023]
Affiliation(s)
- Silvia Lai
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy.
| | - Adolfo Marco Perrotta
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
| | - Silverio Rotondi
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
| | - Francesca Zippo
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
| | - Paolo Menè
- Department of Clinical and Molecular Medicine, Sapienza University of Rome, 00185, Rome, Italy
| | - Lida Tartaglione
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
| | - Chiara Pellicano
- Department of Translational and Precision Medicine, Sapienza University, Rome, Italy
| | - Antonietta Gigante
- Department of Translational and Precision Medicine, Sapienza University, Rome, Italy
| | - Francesca Tinti
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
| | - Mario Mazzei
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
| | - Sandro Mazzaferro
- Department of Translational and Precision Medicine, Nephrology Unit, Sapienza University of Rome, Viale Dell'Università 37, 00185, Rome, Italy
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The role of urinary supersaturations for lithogenic salts in the progression of autosomal dominant polycystic kidney disease. J Nephrol 2022; 36:1011-1018. [DOI: 10.1007/s40620-022-01540-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/20/2022] [Indexed: 12/23/2022]
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Rocha DR, Xue L, Gomes Sousa HM, Carvalho Matos AC, Hoorn EJ, Salih M, Heilberg IP. Urinary Citrate Is Associated with Kidney Outcomes in Early Polycystic Kidney Disease. KIDNEY360 2022; 3:2110-2115. [PMID: 36591350 PMCID: PMC9802559 DOI: 10.34067/kid.0004772022] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
Abstract
Low urinary citrate and crystal deposition accelerated cystogenesis in an experimental model of polycystic kidney disease (PKD).Hypocitraturia, frequently observed in patients with autosomal dominant PKD (ADPKD) could contribute to disease progression.Present findings suggest lower urinary citrate in early PKD was associated with faster eGFR decline and worse kidney survival.
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Affiliation(s)
- Daniel Ribeiro Rocha
- Division of Nephrology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Laixi Xue
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | | | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Mahdi Salih
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
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Blijdorp CJ, Severs D, Musterd-Bhaggoe UM, Gansevoort RT, Zietse R, Hoorn EJ. Serum bicarbonate is associated with kidney outcomes in autosomal dominant polycystic kidney disease. Nephrol Dial Transplant 2021; 36:2248-2255. [PMID: 33377160 PMCID: PMC8643593 DOI: 10.1093/ndt/gfaa283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Metabolic acidosis accelerates progression of chronic kidney disease, but whether this is also true for autosomal dominant polycystic kidney disease (ADPKD) is unknown. METHODS Patients with ADPKD from the DIPAK (Developing Interventions to halt Progression of ADPKD) trial were included [n = 296, estimated glomerular filtration rate (eGFR) 50 ± 11 mL/min/1.73 m2, 2.5 years follow-up]. Outcomes were worsening kidney function (30% decrease in eGFR or kidney failure), annual eGFR change and height-adjusted total kidney and liver volumes (htTKV and htTLV). Cox and linear regressions were adjusted for prognostic markers for ADPKD [Mayo image class and predicting renal outcomes in ADPKD (PROPKD) scores] and acid-base parameters (urinary ammonium excretion). RESULTS Patients in the lowest tertile of baseline serum bicarbonate (23.1 ± 1.6 mmol/L) had a significantly greater risk of worsening kidney function [hazard ratio = 2.95, 95% confidence interval (CI) 1.21-7.19] compared with patients in the highest tertile (serum bicarbonate 29.0 ± 1.3 mmol/L). Each mmol/L decrease in serum bicarbonate increased the risk of worsening kidney function by 21% in the fully adjusted model (hazard ratio = 1.21, 95% CI 1.06-1.37). Each mmol/L decrease of serum bicarbonate was also associated with further eGFR decline (-0.12 mL/min/1.73 m2/year, 95% CI -0.20 to -0.03). Serum bicarbonate was not associated with changes in htTKV or htTLV growth. CONCLUSIONS In patients with ADPKD, a lower serum bicarbonate within the normal range predicts worse kidney outcomes independent of established prognostic factors for ADPKD and independent of urine ammonium excretion. Serum bicarbonate may add to prognostic models and should be explored as a treatment target in ADPKD.
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Affiliation(s)
- Charles J Blijdorp
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - David Severs
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Usha M Musterd-Bhaggoe
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ronald T Gansevoort
- Department of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert Zietse
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ewout J Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
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7
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Borrego Utiel FJ, Herrera Contreras I, Merino García E, Moriana Domínguez C, Ocaña Pérez E, García Cortés MJ. Hypocitraturia is present when renal function is impaired in diverse nephropathies and is not related with serum bicarbonate levels. Int Urol Nephrol 2021; 54:1261-1269. [PMID: 34546556 DOI: 10.1007/s11255-021-02992-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/02/2021] [Indexed: 12/01/2022]
Abstract
BACKGROUND In autosomal dominant polycystic kidney disease (ADPKD) it is frequently found a reduction in urinary citrate of unknown origin. It has been suggested that it could be a marker of acid retention in chronic kidney disease. Our aim was to compare urinary citrate in ADPKD with other nephropathies and to show its relation with serum bicarbonate. METHODS We determined urinary citrate in patients with several nephropathies and varied renal function. We included 291 patients, 119 with glomerular diseases, 116 with ADPKD, 21 with other nephropathies, and 35 patients with normal renal function. RESULTS Urinary citrate was higher in women and in patients with normal renal function. ADPKD patients showed similar values of urinary citrate to patients with glomerular diseases and with other nephropathies. We observed a progressive reduction in urinary citrate with renal impairment, in a comparable way among patients with ADPKD and glomerular diseases. We did not observe a relationship with serum bicarbonate. Serum uric acid levels were significantly higher in patients with glomerular diseases than in ADPKD patients, even after correction with the degree of renal function. CONCLUSIONS Hypocitraturia is not specific of ADPKD but it is also present in all tested nephropathies and is related with renal impairment and not with serum bicarbonate. It could be interesting to study urinary citrate as a marker of renal function and as a prognostic factor.
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Affiliation(s)
| | | | - Enoc Merino García
- Unidad de Gestión Clínica (UGC) de Nefrología, Hospital Universitario de Jaén, Jaén, Spain
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8
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Urinary citrate as a marker of renal function in patients with autosomal dominant polycystic kidney disease. Int Urol Nephrol 2021; 54:873-881. [PMID: 34279821 DOI: 10.1007/s11255-021-02953-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Autosomal dominant polycystic kidney disease (ADPKD) is frequent to find low urinary citrate levels. Recently, it has been suggested that urinary citrate could be a marker of covert metabolic acidosis in chronic kidney disease. OBJECTIVE Our aim was to analyze relationship between urinary citrate levels, renal function, and serum bicarbonate in ADPKD patients. METHODS We determined citrate in 24-h collected urine from ADPKD patients and correlated with glomerular filtration rate (CKD-EPI equation) and serum bicarbonate concentration. RESULTS We included 120 patients, 60% men, eGFR was 71 ± 32 mL/min/1.73 m2. Urinary citrate/creatinine ratio was 195 ± 152 mg/gCr (range 1.2-689) with levels significantly higher in females. Urinary citrate lower than 300 mg/gCr was present in 75% of patients and when considering chronic kidney stages (CKD), we observed reduced levels in 48.8% in CKD1 stage, in 79.4% in CKD2 stage, in 96.2% in CKD3 stage, and in 94.7% of patients in CKD4 stage. Urinary citrate was correlated with serum creatinine (r = - 0.61, p < 0.001) and eGFR (r = 0.55, p < 0.001) in both gender. We did not find any correlation with serum bicarbonate. Using a general linear modeling analysis, we found as predictors of urinary citrate/creatinine ratio to glomerular filtration rate, gender, and age. Lower levels of urinary citrate were accompanied by a decline in urinary osmolality and in renal excretion of calcium and uric acid. In a subgroup of patients, we measured total kidney volume and we found an inverse correlation with urinary citrate levels that disappeared when it was corrected with glomerular filtration rate. CONCLUSIONS Urinary citrate is very frequently reduced in ADPKD patients being present from very early CKD stages. Their levels in urine are inversely correlated with glomerular filtration rate and it is not related with serum bicarbonate concentration. We think that it would be interesting to study urinary citrate as a marker of chronic kidney disease in ADPKD patients.
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Bargagli M, Dhayat NA, Anderegg M, Semmo M, Huynh-Do U, Vogt B, Ferraro PM, Fuster DG. Urinary Lithogenic Risk Profile in ADPKD Patients Treated with Tolvaptan. Clin J Am Soc Nephrol 2020; 15:1007-1014. [PMID: 32527945 PMCID: PMC7341771 DOI: 10.2215/cjn.13861119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/24/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND OBJECTIVES Nephrolithiasis is a common health problem in autosomal dominant polycystic kidney disease (ADPKD) and significantly contributes to patient morbidity. Recently, Tolvaptan has been introduced for the treatment of ADPKD, but whether it is associated with alterations of the urinary lithogenic risk profile remains unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We conducted an analysis of participants enrolled in the Bern ADPKD registry, a prospective observational cohort study. Twenty-four-hour urine analyses were performed at baseline and then at yearly follow-ups. Relative supersaturation ratios for calcium oxalate, brushite, and uric acid were calculated with the program EQUIL2. Unadjusted and multivariable mixed-effects linear regression models, adjusted for age, sex, body mass index, eGFR, net acid excretion, and height-adjusted total kidney volume, were used to assess the association of Tolvaptan with urinary parameters relevant for kidney stone formation. The maximum individual follow-up time was 3 years, median follow-up time 1.9 years, and cumulative follow-up time 169 years. RESULTS In total, 125 participants (38 with and 87 without Tolvaptan treatment) were included in the analysis. In multivariable analysis, Tolvaptan treatment was associated [adjusted estimate of the difference between Tolvaptan and no Tolvaptan; 95% confidence interval (CI)] with lower urine relative supersaturation ratios for calcium oxalate (-0.56; 95% CI, -0.82 to -0.3; P<0.001), brushite (-0.33; 95% CI, -0.54 to -0.11; P=0.004), and uric acid (-0.62; 95% CI, -0.88 to -0.37; P<0.001), and with higher urine citrate in mmol/mmol creatinine per day (0.25; 95% CI, 0.05 to 0.46; P=0.02) and calcium in mmol/mmol creatinine per day (0.31; 95% CI, 0.09 to 0.53; P=0.006) excretion. In addition, Tolvaptan treatment was associated with lower net acid excretion in mEq/mmol creatinine per day (-0.54; 95% CI, -0.90 to -0.17; P=0.004) and higher net gastrointestinal alkali absorption in mEq/mmol creatinine per day (0.57; 95% CI, 0.26 to 0.88; P<0.001). CONCLUSIONS Tolvaptan treatment is associated with a significantly improved urinary lithogenic risk profile in patients with ADPKD.
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Affiliation(s)
- Matteo Bargagli
- U.O.C. Nefrologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
- Università Cattolica del Sacro Cuore, Rome, Italy
| | - Nasser A. Dhayat
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Manuel Anderegg
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Mariam Semmo
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Uyen Huynh-Do
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Bruno Vogt
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Pietro Manuel Ferraro
- U.O.C. Nefrologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
- Università Cattolica del Sacro Cuore, Rome, Italy
| | - Daniel G. Fuster
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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10
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Wang K, Zelnick LR, Chen Y, Hoofnagle AN, Watnick T, Seliger S, Kestenbaum B. Alterations of Proximal Tubular Secretion in Autosomal Dominant Polycystic Kidney Disease. Clin J Am Soc Nephrol 2019; 15:80-88. [PMID: 31628117 PMCID: PMC6946073 DOI: 10.2215/cjn.05610519] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/13/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND OBJECTIVES In autosomal dominant polycystic kidney disease (ADPKD), the GFR often remains normal despite significant nephron loss. Proximal tubular secretory clearance may be reduced in ADPKD before detectable changes in GFR. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We used targeted mass spectrometry to quantify secretory solutes from blood and urine samples from 31 patients with ADPKD and preserved GFR (mean eGFR =111±11 ml/min per 1.73 m2) and 25 healthy control individuals as well as from 95 patients with ADPKD and reduced GFR (mean eGFR =53±21 ml/min per 1.73 m2) and 92 individuals with non-ADPKD CKD. We used linear regression to compare the fractional excretion of each solute between ADPKD and control groups. Among 112 patients with ADPKD, we used linear regression to determine associations of solute fractional excretion with height-adjusted total kidney volume. RESULTS After adjusting for demographics, clinical characteristics, and kidney function measures, the fractional excretions of three secretory solutes were lower in patients with ADPKD and preserved GFR compared with healthy individuals: 52% lower cinnamoylglycine excretion (95% confidence interval, 24% to 70%), 53% lower tiglylglycine excretion (95% confidence interval, 23% to 71%), and 91% lower xanthosine excretion (95% confidence interval, 83% to 95%). In addition to lower excretions of tiglylglycine and xanthosine, patients with ADPKD and reduced GFR also demonstrated 37% lower dimethyluric acid excretion (95% confidence interval, 21% to 50%), 58% lower hippurate excretion (95% confidence interval, 48% to 66%), 48% lower isovalerylglycine excretion (95% confidence interval, 37% to 56%), and 31% lower pyridoxic acid excretion (95% confidence interval, 16% to 42%) compared with patients with non-ADPKD CKD and comparable eGFR. Among patients with ADPKD, solute fractional excretions were not associated with differences in kidney volume. CONCLUSIONS Patients with ADPKD and preserved and reduced GFR demonstrate lower tubular secretory solute excretion compared with healthy controls and patients with non-ADPKD CKD. Our results suggest that tubular secretion is impaired in ADPKD independent of GFR.
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Affiliation(s)
- Ke Wang
- Division of Nephrology, Department of Medicine and .,Division of Nephrology, Kidney Research Institute, Kidney Research Institute, Seattle, Washington; and
| | - Leila R Zelnick
- Division of Nephrology, Department of Medicine and.,Division of Nephrology, Kidney Research Institute, Kidney Research Institute, Seattle, Washington; and
| | - Yan Chen
- Division of Nephrology, Kidney Research Institute, Kidney Research Institute, Seattle, Washington; and.,Departments of Epidemiology and
| | - Andrew N Hoofnagle
- Division of Nephrology, Kidney Research Institute, Kidney Research Institute, Seattle, Washington; and.,Laboratory Medicine, University of Washington, Seattle, Washington
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland, Baltimore, Maryland
| | - Stephen Seliger
- Division of Nephrology, Department of Medicine, University of Maryland, Baltimore, Maryland
| | - Bryan Kestenbaum
- Division of Nephrology, Department of Medicine and.,Division of Nephrology, Kidney Research Institute, Kidney Research Institute, Seattle, Washington; and
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11
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Nutritional therapy in autosomal dominant polycystic kidney disease. J Nephrol 2018; 31:635-643. [PMID: 29344814 DOI: 10.1007/s40620-018-0470-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/29/2017] [Indexed: 02/08/2023]
Abstract
CKD-related nutritional therapy (NT) is a crucial cornerstone of CKD patients' treatment, but the role of NT has not been clearly investigated in autosomal dominant polycystic kidney disease (ADPKD). Several clinical studies have focused on new pharmacological approaches to delay cystic disease progression, but there are no data on dietary interventions in ADPKD patients. The aim of this paper is to analyze the evidence from the literature on the impact of five nutritional aspects (water, sodium, phosphorus, protein intake, and net acid load) in CKD-related ADPKD extrapolating-where information is unavailable-from what occurs in CKD non-ADPKD patients Sodium intake restriction could be useful in decreasing the growth rate of cysts. Although further evidence is needed, restriction of phosphorus and protein intake restriction represent cornerstones of the dietary support of renal non-ADPKD patients and common sense can guide their use. It could be also helpful to limit animal protein, increasing fruit and vegetables intake together with a full correction of metabolic acidosis. Finally, fluid intake may be recommended in the early stages of the disease, although it is not to be prescribed in the presence of moderate to severe reduction of renal function.
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12
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Gao C, Zhang L, Zhang Y, Wallace DP, Lopez-Soler RI, Higgins PJ, Zhang W. Insights into cellular and molecular basis for urinary tract infection in autosomal-dominant polycystic kidney disease. Am J Physiol Renal Physiol 2017; 313:F1077-F1083. [PMID: 28794066 DOI: 10.1152/ajprenal.00279.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/24/2017] [Accepted: 08/07/2017] [Indexed: 12/27/2022] Open
Abstract
Urinary tract infection (UTI) is a broad term referring to an infection of the kidneys, ureters, bladder, and/or urethra. Because of its prevalence, frequent recurrence, and rising resistance to antibiotics, UTI has become a challenge in clinical practice. Autosomal-dominant polycystic kidney disease (ADPKD) is the most common monogenic disorder of the kidney and is characterized by the growth of fluid-filled cysts in both kidneys. Progressive cystic enlargement, inflammation, and interstitial fibrosis result in nephron loss with subsequent decline in kidney function. ADPKD patients frequently develop UTI; however, the cellular and molecular mechanisms responsible for the high UTI incidence in ADPKD patients remain virtually unaddressed. Emerging evidence suggests that α-intercalated cells (α-ICs) of the collecting ducts function in the innate immune defense against UTI. α-ICs inhibit bacterial growth by acidifying urine and secreting neutrophil gelatinase-associated lipocalin (NGAL) that chelates siderophore-containing iron. It is necessary to determine, therefore, if ADPKD patients with recurrent UTI have a reduced number and/or impaired function of α-ICs. Identification of the underlying cellular and molecular mechanisms may lead to the development of novel strategies to reduce UTI in ADPKD.
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Affiliation(s)
- Chao Gao
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York
| | - Long Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York
| | - Ye Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York
| | - Darren P Wallace
- Departments of Internal Medicine and Physiology and The Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas; and
| | - Reynold I Lopez-Soler
- Department of Surgery, Division of Transplantation, Albany Medical College, Albany, New York
| | - Paul J Higgins
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York
| | - Wenzheng Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York;
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Pietrzak-Nowacka M, Safranow K, Palacz J, Gołembiewska E, Marchelek-Myśliwiec M, Ciechanowski K. Association of kidney and cysts dimensions with anthropometric and biochemical parameters in patients with ADPKD. Ren Fail 2015; 37:798-803. [DOI: 10.3109/0886022x.2015.1033608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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14
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Ali H, Hussain N, Naim M, Zayed M, Al-Mulla F, Kehinde EO, Seaburg LM, Sundsbak JL, Harris PC. A novel PKD1 variant demonstrates a disease-modifying role in trans with a truncating PKD1 mutation in patients with autosomal dominant polycystic kidney disease. BMC Nephrol 2015; 16:26. [PMID: 25880449 PMCID: PMC4357204 DOI: 10.1186/s12882-015-0015-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 02/09/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common form of Polycystic Kidney Disease (PKD) and occurs at a frequency of 1/800 to 1/1000 affecting all ethnic groups worldwide. ADPKD shows significant intrafamilial phenotypic variability in the rate of disease progression and extra-renal manifestations, which suggests the involvement of heritable modifier genes. Here we show that the PKD1 gene can act as a disease causing and a disease modifier gene in ADPKD patients. METHODS Clinical evaluation of a family with ADPKD was performed to diagnose and assess disease progression in each individual. PKD1 was genotyped in each individual by targeted sequencing. RESULTS Targeted screening analysis showed that the patients with ADPKD in the family had the PKD1: p.Q2243X nonsense mutation. A more severe disease phenotype, in terms of estimated Glomerular Filtration Rate (eGFR) and total kidney volume, was observed in two patients where in addition to the mutation, they carried a novel PKD1 variant (p.H1769Y). Other patients from the same family carrying only the (p.Q2243X) mutation showed milder disease manifestations. CONCLUSION ADPKD shows significant intrafamilial phenotypic variability that is generally attributed to other modifier genes. In this rare case, we have shown that a variant at PKD1, in trans with the PKD1 mutation, can also act as a modifier gene in ADPKD patients. Understanding the molecular mechanism through which the gene exerts its disease modifying role may aid our understanding of the pathogenesis of ADPKD.
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Affiliation(s)
- Hamad Ali
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Health Sciences Center, Kuwait University, Jabriya, Kuwait.
| | - Naser Hussain
- Division of Nephrology, Mubarak Al-Kabeer Hospital, Ministry of Health, Jabriya, Kuwait.
| | - Medhat Naim
- Division of Nephrology, Mubarak Al-Kabeer Hospital, Ministry of Health, Jabriya, Kuwait.
| | - Mohamed Zayed
- Department of Radio diagnosis, Mubarak Al-Kabeer Hospital, Ministry of Health, Jabriya, Kuwait.
| | - Fahd Al-Mulla
- Department of Pathology, Faculty of Medicine, Health Sciences Center, Kuwait University, Jabriya, Kuwait.
| | - Elijah O Kehinde
- Department of Surgery, Division of Urology, Faculty of Medicine, Health Sciences Center, Kuwait University, Jabriya, Kuwait.
| | - Lauren M Seaburg
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, USA.
| | - Jamie L Sundsbak
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, USA.
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, USA.
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Ferraz RRN, Fonseca JM, Germino GG, Onuchic LF, Heilberg IP. Determination of urinary lithogenic parameters in murine models orthologous to autosomal dominant polycystic kidney disease. Urolithiasis 2014; 42:301-7. [PMID: 24817661 PMCID: PMC5602548 DOI: 10.1007/s00240-014-0664-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/15/2014] [Indexed: 10/25/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD), a genetic disease caused by mutations in PKD1 or PKD2 genes, is associated with a high prevalence of nephrolithiasis. The underlying mechanisms may encompass structural abnormalities resulting from cyst growth, urinary metabolic abnormalities or both. An increased frequency of hypocitraturia has been described in ADPKD even in the absence of nephrolithiasis, suggesting that metabolic alterations may be associated with ADPKD per se. We aimed to investigate whether non-cystic Pkd1-haploinsufficient (Pkd1(+/-)) and/or nestin-Cre Pkd1-targeted cystic (Pkd1(cond/cond):Nestin(cre)) mouse models develop urinary metabolic abnormalities potentially related to nephrolithiasis in ADPKD. 24-h urine samples were collected during three non-consecutive days from 10-12 and 18-20 week-old animals. At 10-12 weeks of age, urinary oxalate, calcium, magnesium, citrate and uric acid did not differ between test and their respective control groups. At 18-20 weeks, Pkd1(+/-) showed slightly but significantly higher urinary uric acid vs. controls while cystic animals did not. The absence of hypocitraturia, hyperoxaluria and hyperuricosuria in the cystic model at both ages and the finding of hyperuricosuria in the 18-20 week-old animals suggest that anatomic cystic distortions per se do not generate the metabolic disturbances described in human ADPKD-related nephrolithiasis, while Pkd1 haploinsufficiency may contribute to this phenotype in this animal model.
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Affiliation(s)
| | | | | | - Luiz Fernando Onuchic
- Division of Nephrology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil
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16
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Nishiura JL, Neves RFCA, Eloi SRM, Cintra SMLF, Ajzen SA, Heilberg IP. Evaluation of nephrolithiasis in autosomal dominant polycystic kidney disease patients. Clin J Am Soc Nephrol 2009; 4:838-44. [PMID: 19339428 DOI: 10.2215/cjn.03100608] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND AND OBJECTIVES Nephrolithiasis (LIT) is more prevalent in patients with autosomal dominant polycystic kidney disease (ADPKD) than in the general population. Renal ultrasonography may underdetect renal stones because of difficulties imposed by parenchymal and/or cyst wall calcifications. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A total of 125 patients with ADPKD underwent ultrasonography and unenhanced computed tomography (CT) scan, routine blood chemistry, and spot and 24-h urine collections. RESULTS CT scan detected calculi in 32 patients, including 20 whose previous ultrasonography revealed no calculi. The percentage of hypocitraturia was high but not statistically different between patients with ADPKD+LIT or ADPKD. Hyperuricosuria and distal renal tubular acidosis were less prevalent but also did not differ between groups, whereas hyperoxaluria was significantly higher in the former. Hypercalciuria was not detected. Renal volume was significantly higher in patients with ADPKD+LIT versus ADPKD, and a stepwise multivariate logistic regression analysis showed that a renal volume >or=500 ml was a significant predictor of LIT in patients with ADPKD and normal renal function, after adjustments for age and hypertension. CONCLUSIONS CT scan was better than ultrasonography to detect LIT in patients with ADPKD. Larger kidneys from patients with ADPKD were more prone to develop stones, irrespective of the presence of metabolic disturbances.
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Affiliation(s)
- José L Nishiura
- Nephrology Division, Universidade Federal de São Paulo, São Paulo, Brazil
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17
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Love K, Yeo FE. Cystinuria in a patient with polycystic kidney disease. NDT Plus 2009; 2:30-3. [PMID: 25949280 PMCID: PMC4421477 DOI: 10.1093/ndtplus/sfn166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2008] [Accepted: 10/06/2008] [Indexed: 11/13/2022] Open
Abstract
Cystinuria is a rare autosomal recessive metabolic disorder of renal and intestinal cystine transport. Cystine stones are found in only 1–2% of all stone formers. Patients with cystinuria are at high risk for nephrolithiasis and subsequent morbidity. Our patient is a 37-year-old male who presented for routine follow-up for polycystic kidney disease (PKD). He denied any history of passing nephroliths. He had no family history of PKD or personal history of kidney stones. Serum creatinine was 1.2 mg%. On routine urine microscopy, he was found to have multiple hexagonal cystine crystals. Urine pH was 7.5. Renal CT scan revealed enlarged polycystic kidneys and scattered bilateral intra-renal calculi. Urinary quantification of cystine was 1645 mg/day (normal excretion rate 30 mg/day). Patients with PKD are at increased risk for nephrolithiasis for a number of reasons including urinary acidification, concentrating defects and hypocitraturia. The molecular, cellular and genetic basis for cystinuria is distinctly different and presumably unrelated to the genetic defects in PKD. We suspect that the occurrence of these two unrelated genetic diseases in the same patient is a coincidental finding. Even after a thorough review of the published literature, we were unable to find a genetic relationship between cystinuria and cystic renal diseases. To our knowledge, this is the first report of a finding of cystinuria in an adult with PKD.
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Affiliation(s)
- Kate Love
- Internal Medicine Department, National Naval Medical Center
| | - Fred E Yeo
- Internal Medicine Department, Nephrology Division , Uniformed Services University of the Health Sciences , Bethesda, MD , USA
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18
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Abstract
Autosomal dominant polycystic kidney disease is the most prevalent, potentially lethal, monogenic disorder. It is associated with large interfamilial and intrafamilial variability, which can be explained to a large extent by its genetic heterogeneity and modifier genes. An increased understanding of the disorder's underlying genetic, molecular, and cellular mechanisms and a better appreciation of its progression and systemic manifestations have laid out the foundation for the development of clinical trials and potentially effective treatments.
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Affiliation(s)
| | | | - Yves Pirson
- Cliniques St Luc, Université Catholique de Louvain, Brussels, Belgium
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19
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Gambaro G, Fabris A, Puliatta D, Lupo A. Lithiasis in cystic kidney disease and malformations of the urinary tract. ACTA ACUST UNITED AC 2006; 34:102-7. [PMID: 16416113 DOI: 10.1007/s00240-005-0019-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2005] [Indexed: 11/27/2022]
Abstract
The prevalence of renal stones in renal cystic and malformative conditions exceeds the prevalence of renal stones in the general population, suggesting that the above-mentioned cystic and malformative disorders favor stone formation. Urinary stasis is generally assumed to play a major part in the pathogenesis of the nephrolithiasis associated with distorted renal anatomy due to a delayed washout of crystals and risk of urinary infections. However metabolic factors are also important in the pathogenesis of stones in these conditions. Indeed, metabolic abnormalities have been observed in the majority of stone-forming patients with conditions such as horseshoe kidney and ureteropelvic junction obstruction. Five different models of stone formation can be identified, depending on stone composition, risk of infection stones, and pathogenesis of renal cystic and malformative conditions. A proper metabolic evaluation should be conducted to diagnose specific, treatable metabolic disorders, thereby reducing the frequency of recurrent stone disease in these conditions as well.
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Affiliation(s)
- G Gambaro
- Divisione di Nefrologia, Dipartimento di Scienze Biomediche e Chirurgiche, Università di Verona, Ospedale Maggiore, P.le Stefani 1, 37126, Verona, Italy.
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20
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Abstract
BACKGROUND Few treatments are available to slow the progression to renal failure in autosomal dominant polycystic kidney disease (PKD). In an animal model of PKD, the male heterozygous Han:SPRD rat, intake of a solution of potassium citrate plus citric acid (KCitr) from age one to three months prevented a decline in glomerular filtration rate (GFR). The present study tested whether this beneficial effect is sustained and explored handling of citrate and ammonia in normal and cystic kidneys. METHODS Rats were provided with tap water or citrate solutions to drink, and clearance and survival studies were performed. RESULTS The GFRs of rats with PKD that consumed KCitr from one month of age were normal at six months of age, while those of their counterparts on water were about one third of normal. Long-term KCitr treatment extended the average life span of rats with PKD from 10 to 17 months. Compared with normal rats, water-drinking rats with PKD had higher plasma [citrate], renal cortical [citrate], and fractional excretion of citrate, and lower rates of renal citrate consumption, ammonia synthesis, and ammonia excretion. Cortical PNH3 was not elevated in cystic kidneys. Intake of Na3 citrate/citric acid solution or K3 citrate solution, but not ammonium citrate/citric acid solution, prevented a decline in GFR in three-month-old rats with PKD. CONCLUSIONS Rats with PKD show abnormal renal handling of citrate and ammonia. Citrate salts that have an alkalinizing effect preserve GFR and extend survival.
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Affiliation(s)
- G A Tanner
- Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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21
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Complement-mediated renal injury: Mechanisms and role of membrane regulators of complement. Clin Exp Nephrol 1998. [DOI: 10.1007/bf02480454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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22
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Abstract
In autosomal dominant polycystic kidney disease (ADPKD), the genetic defect results in the slow growth of a multitude of epithelial cysts within the renal parenchyma. Cysts originate within the glomeruli and all tubular structures, and their growth is the result of proliferation of incompletely differentiated epithelial cells and the accumulation of fluid within the cysts. The majority of cysts disconnect from tubular structures as they grow but still accumulate fluid within the lumen. The fluid accumulation is the result of secretion of fluid driven by active transepithelial Cl- secretion. Proliferation of the cells and fluid secretion are activated by agonists of the cAMP signaling pathway. The transport mechanisms involved include the cystic fibrosis transmembrane conductance regulator (CFTR) present in the apical membrane of the cystic cells and a bumetanide-sensitive transporter located in the basolateral membrane. A lipid factor, called cyst activating factor, has been found in the cystic fluid. Cyst activating factor stimulates cAMP production, proliferation, and fluid secretion by cultured renal epithelial cells and also is a chemotactic agent. Cysts also appear in the intrahepatic biliary tree in ADPKD. Normal ductal cells secrete Cl- and HCO3-. The cystic ductal cell also secretes Cl-, but HCO3- secretion is diminished, probably as the result of a lower population of Cl-/HCO3- exchangers in the apical membrane as compared with the normal cells. Some segments of the normal renal tubule are also capable of utilizing CFTR to secrete Cl-, particularly the inner medullary collecting duct. The ability of Madin-Darby canine kidney cells and normal human kidney cortex cells to form cysts in culture and to secrete fluid and the functional similarities between these incompletely differentiated, proliferative cells and developing cells in the intestinal crypt and in the fetal lung have led us to suggest that Cl- and fluid secretion may be a common property of at least some renal epithelial cells in an intermediate stage of development. The genetic defect in ADPKD may not directly affect membrane transport mechanisms but rather may arrest the development of certain renal epithelial cells in an incompletely differentiated, proliferative stage.
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Affiliation(s)
- L P Sullivan
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City 66160, USA
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23
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Pabico RC, McKenna BA, Freeman RB. Renal tubular dysfunction in patients with cystic disease of the kidneys. Urology 1998; 51:156-60. [PMID: 9610573 DOI: 10.1016/s0090-4295(98)00081-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To define the renal tubular functional abnormalities in patients with cystic disease of the kidneys. METHODS Patients with autosomal dominant polycystic kidney disease (ADPKD) (n = 4) and medullary sponge kidneys (MSK) (n = 3) with normal glomerular filtration rate (GFR), determined by inulin clearance, and effective renal plasma flow (ERPF), measured by p-aminohippurate clearance, underwent measurement of proximal and distal tubular functions. Proximal tubular functions were determined by the maximum reabsorption of glucose (TmGlucose) and the maximum secretion of p-aminohippurate (TmPAH). Distal tubular functions were measured by the maximum urinary concentrating and diluting mechanisms, and the urinary acidification response to acid load. RESULTS TmGlucose was low in both groups (209 +/- 25 mg/min/1.73 m2 in the ADPKD group and 110 +/- 28 mg/min/1.73 m2 in the MSK, compared with 375 +/- 40 mg/min/1.73 m2 in healthy controls; P < 0.05). Likewise, TmPAH was significantly diminished in patients with ADPKD (72 +/- 6 mg/min/1.73 m2) and MSK (63 +/- 5 mg/min/1.73 m2) when compared with healthy controls (89 +/- 4 mg/min/1.73 m2; P < 0.05). Urinary maximum concentration after fluid deprivation was impaired in both ADPKD and MSK patients, but the diluting mechanism was intact. Finally, the ability to excrete urinary ammonium and titratable acids following an oral acid load was inadequate in both the ADPKD and MSK groups. CONCLUSIONS Proximal and distal tubular functions are impaired in patients with ADPKD and MSK when GFR and ERPF are normal, indicating tubular disruption by the cysts and the alteration of the tubulo-interstitial vascular relationship.
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Affiliation(s)
- R C Pabico
- Department of Medicine, University of Rochester Medical Center, New York 14642, USA
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Jordan M, Cohen EP, Roza A, Adams MB, Johnson C, Gluck SL, Bastani B. An immunocytochemical study of H+ ATPase in kidney transplant rejection. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1996; 127:310-4. [PMID: 9273365 DOI: 10.1016/s0022-2143(96)90100-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Kidney transplant rejection may be accompanied by defective urinary acidification. Its pathogenesis is unknown. There are shared histologic features between kidney transplant rejection and the distal renal tubular acidosis (RTA) of Sjogren syndrome, which led us to hypothesize that deficient collecting duct H+ adenosine triphosphatase (ATPase) expression--which is lacking in the RTA of Sjogren syndrome - may cause the RTA of kidney transplant rejection. Six kidney transplant recipients with biopsy evidence for rejection and two control subjects were studied physiologically and by immunohistochemistry. We found defective urinary acidification in all 6 kidney transplant patients. Ammonium excretion was diminished in relation to the degree of azotemia. There was an abnormal response to furosemide in all 6, suggesting distal tubular dysfunction. Distal H+ ATPase staining was reduced in relation to the degree of azotemia, although it was not totally absent even in the worst case. This was paralleled by the urinary PCO2 response. Both control subjects had good urine PCO2 and H+ ATPase staining and adequate urine pH response to furosemide. They had reduced urinary ammonium (NH4) concentrations in relation to modest azotemia. We conclude that kidney transplant rejection may be accompanied by defective urinary acidification, which is not primarily due to a lack of H+ ATPase. The RTA of kidney transplant rejection appears to result from defective ammonium excretion, generalized distal tubular malfunction, and--in severe cases--from a reduction in distal nephron H+ ATPase expression.
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Affiliation(s)
- M Jordan
- Department of Surgery and Medicine, Medical College of Wisconsin, Milwaukee 53226, USA
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Abstract
Polycystic kidney disease (PKD) represents the most common inherited cause of chronic renal failure. PKD is a relatively uncommon cause of chronic renal failure or mortality in childhood and adolescence, but is nevertheless often responsible for symptoms of renal disease. Current research into the pathogenesis of PKD suggests that disturbance of the normal regulation of growth and development of tubular epithelium is intrinsic to cyst formation and growth. Features of cystic epithelium that are analogous to earlier stages of renal development include altered composition of the extracellular matrix, abnormal cell proliferation, and the persistence of a secretory pattern of fluid and electrolyte transport. The potential for early diagnosis and intervention in PKD makes it an area of great interest to the pediatric nephrologist. Animal and in vitro studies have achieved modification of cyst growth by reduction of dietary protein, use of amiloride and its analogs, antagonism of the epidermal growth factor receptor system, anti-inflammatory therapy, and most recently with the use of taxol, an agent that inhibits microtubule assembly. PKD may represent an area in which childhood diagnosis and intervention will have a significant impact on the prevalence of chronic renal failure in adult life.
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Affiliation(s)
- M R Ogborn
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada
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